FS-6460 --resolve fix leaked RTP ports that cause mod_skinny to fail after N calls

src/mod/endpoints/mod_skinny/mod_skinny.c

@@ -875,6 +875,10 @@ switch_status_t channel_on_destroy(switch_core_session_t *session)
 		if (switch_core_codec_ready(&tech_pvt->write_codec)) {
 			switch_core_codec_destroy(&tech_pvt->write_codec);
 		}
+
+		if (switch_rtp_ready(tech_pvt->rtp_session)) {
+			switch_rtp_destroy(&tech_pvt->rtp_session);
+		}
 	}
 
 	switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG, "%s CHANNEL DESTROY\n", switch_channel_get_name(channel));